E3D bowden converstion

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E3D bowden converstion

Postby plexus » 2015-May-Tue-22-May

I've completed a bowden conversion of my PB+. it went pretty well except the mounting plate on the printer needed to be routed out to fit the extruder carrier. The E3D hotend is too short to clear the bottom of the carrier without replacing the stock mount.

It works. the jury is still out however on whether its better (for me). I do like the uncluttered nature of it and getting all that forward leaning weight off the X bearings would be a good thing. but in terms of print quality and other issues... unsure...

There is definitely an issue with filament hysteresis in that there is more ooze from the nozzle in a static situation after some filament feed. I suppose retraction is the answer here. also I have had some jams but I think I need to couple the hot end heat sink fan better to the heat sink. i notice that the wades extruder carves notches out in the filament which might be causing more friction in the bowden tube. i will need to experiment with reducing the hob pressure.

However, I am unsure if going to bowden is worth the effort. I did some quick speed tests and although the printer seems to handle the higher speeds better, there is a filament feed issue. it looks like I need to increase the hot end temp with faster printing. I did try this but the results were not conclusive. I will need more time to try and optimize the settings for this set up. but right now I can't say its worth it.

Perhaps with the right settings and using the Volcano hot end the benefits of bowden will be realized. but for now... I will keep you posted. I suspect that bowden, at least on my printer, may not have enough observable evidence to justify the issues. but I will try.

(the pictures are in reverse order from the sequence of assembly due to the way tapatalk posts them. sorry)

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E3D bowden converstion

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Re: E3D bowden converstion

Postby plexus » 2015-May-Thu-00-May

I started out tonight with failures of the bowden set up. I was having trouble with jams. its a whole new set of troubleshooting items with bowden. i ended up removing the piece of filament in the tube and running fresh filament through it. i also loosened up on the hob pressure because I was thinking the grooves were adding diameter to the filament causing extra friction. not sure if that was the problem but it started printing again. then I realized the fittings the tube is in were pushing in and out with suck and prime. i surmised that the tube should not move and I so I pressed them in as tight as I could. this really helped with hysteresis and oozing. i also set kisslicer to retract 3mm from what i was using 1mm, and increased the suck and prime speeds.

Before the tuning I printed the marvin below. it didn't go well. its 200
um layers.

After the tuning I printed the bracelet with 100um layers fairly quickly. this turned out great and I don't think direct feed set up could have done this. I was getting strange rippling in the surface at 100um or below. I will try 50 at some point.

There is ripple resolving in the photos however in real life its not as severe as it looks. it appears to be from the interaction of ripple imparted by, I think, stepper motor quantization. the ripple pattern is difference on each face depending on the X and Y speed in that location. its interesting that it can resolve this.

I left the brim base on the bracelet and it makes a nice little bowl. it is very delicate with only a 0.6mm wall. single layer. but it has good layer adhesion and can be bent to some degree with no sign of delamination.


I figured with this success end the night on a good note.
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Re: E3D bowden converstion

Postby plexus » 2015-May-Thu-09-May

As you could imagine, filament feed through the tube is critical. even the amount of damage a hob does to the filament can significantly increase friction to the point where there are problems. even in the 100um print below there are still feed issues (which you can see as layer high holes in the print). the length of the tube is a factor as so positioning the extruder is important to reduce the length of tube. I am using a 1 m tube. I still haven't figured out a good place for the extruder so I won't cut it down until I have that sorted out. its a bit of a chicken/egg issue because print quality is also a factor of extruder location and tube length. but I can't figure out the best location and length without working with it more. It's more of a space issue for me as I don't have a lot of space to place things. Instinctively the extruder should be above the print bed, but then as the hot end rises in Z the tube will bend. bends are also a factor. so there is a whole bunch more stuff to tweek and fiddle with.

So I am going to still say the jury is still out on bowden for me. but I will keep working with it and see how far I can take it. I do like the idea but I am unsure of the execution compared to the "old way".
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Re: E3D bowden converstion

Postby plexus » 2015-May-Thu-23-May

The proof was in the pudding: I got a small print job today and figured lets try the bowden out. if it passes this test then great. result: fail!

It was printing but there was evidence of misfeed in the walls. there were holes in the layers on the wall. as if filament stop flowing for a short while during a loop, like 1-3mm. this looked like delamination or holes that are a layer high and 1-3mm wide. here and there. when I took the 1m of filament out of the tube after the print I could see areas on the filament that had skipped in the hob bolt. just little scrapes but enough evidence to show there was misfeeding. so I worked out the shorted tube length and cut off about 20mm. tried again. same thing.

At this point I questioned the value of trying to get bowden to work. since I didn't know where to go from there besides messing with nob idle pressure, tube angle, trying to get the extruder closer etc. I decided it was faster to switch back to direct feed wades. so I did and have been printing very lovely PLA prints for my client.

So for now, my bowden attempt didn't work out. total cost of bowden specific parts about $40 canadian so no big deal.

I left the direct drive hot end in place with the E3D plastic plate and just bolted the extruder to the top. works fine. I am just using the bowden feed heat sink with direct feed. it works and its easier than switching the whole hot end out.

If you have any eureka idea about how I can get bowden to work let me know. also, what ARE the benfits of bowden anyway? is it just potential faster speed and less bearing wear? not sure it would be worth the hassle. also i had a number of failures resulting in having to remove the filament from the tube and discard it. thats 3m of filament wasted. also a concern.
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Re: E3D bowden converstion

Postby bbrown64 » 2015-Jul-Sun-07-Jul

I sure wish the Simple Metal 1403 would be easier to adapt a E3D-V6 to. I have made the mod to accept the E3D-V6. But I do not like the little adapter that has to be printed. There simply is not enough of the E3D-V6 sticking up into the extruder. Only about 2-3mm is all that holds the hotend into the extruder.
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